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WerewulfX writes "CNN reports: "In a phenomenon that has scientists puzzled, the Earth is right on schedule for a fifth straight year."Update yeah, this is a repost. Whatever- it's a holiday. Nothing else to post :)

When (greater) Sweden was going to change from Julian to Gregorian calendar they stuffed it up, got one day out of sync with all Julian countries, so to get back in sync they added an extra leap day, creating the only 30th Feb in history.

They eventually made the change from Julian in 1753 by having (gregorian) 1st Mar 1753 after (julian) 17 Feb 1753 removing ten days.

Makes a leap second seem a bit insignificant....

If you have no idea about Julian (as in Ceasar) and Gregorian (as in pope) calendars, have a look here [hermetic.ch]

I was born on Feb 30, 1969. At least my fake ID says so. Funny; not one person noticed it in the five years or so I used that fake ID consistently. Not even when I asked them straight out what was wrong with the data they were looking at.

People react immediately at Feb 29 of whatever year and check if it's a leap year. Feb 30 just passes as another date.

Hell, I even have a library card using that fake ID. Even though it's been a long time since I used (or needed) the older identity, I still think it's kin

This ranks right up there with the folks that were supposed to prevent 9/11 and with doctors that let people die just because they have injuries too serious to fix! Dupes on Slashdot SHOULD ruin everyone's day - neigh - LIFE!!! Editors on Slashdot that allow dupes on a holiday should be shot, burned, and their ashes scattered over the local sewage treatment plant.
This is seriously a serious situation. A free (unless you're a subscriber) service that posts a duplicate story. I think we should outright

Heal itself? That implies that there is something natural about the 24-hour day. The Earth's rotation rate has been decreasing for billions of years. An Earth day was approximately 18 hours in duration 900 million years ago.

We can estimate how long a day was in the past based on current trends. But as this article shows, that may not be accurate. The article says the discovery of leap seconds is a side effect of the invention of the atomic clock in 1955. That means we've had not quite 50 years to observe trends. For the last 5 the trend has been different than in the past, and we have no clue why. That's over 10% of the sample data that breaks the trend, which isn't a small amount.

Wow! That is so cool that you were actually there to measure the length of a day! So, like, you've got a really good pension plan, right? Do you still have the same clock?

Or is this just more uniformitarian assumptions masquerading as science?

Oh no, he was there... I saw him. He was a total ass back then... knocking out all the hot women and dragging them back to his cave without even killing them dinner first. And, sonney, you think your leap-seconds are bad these days? Well, in my day, on the way

So, does this mean that the acceleration of the earth has changed, and if so, does that that mean we will continue to slow? If we do slow, won't the gravity of the sun effect out orbit? Will we see more el ninjo effects, or other wierd phenomenon?
One second could be a big deal.

Exactly how do they figure out where the Earth is supposed to be down to a given second?
I understand Atomic clocks and how they work - but I don't understand how scientists can deduce where the earth should be to the exact second and correct it as such.

But it would seem to me that any small shift of the telescope would cause a large error.What if the telescope's foundation settles?

I'm thinking that one cannot take much for granted when measuring the position of the Earth to within one second of time.

Our continents are drifting. One would think that plate tectonics wouldn't have much of an effect, but again we are measuring the position that the earth is suppose to be in within one second of time. Wow! That can't be easy.

"That means that if the Earth leaves out ONE SECOND of movement, it loses almost 20 miles."

20 miles is nothing when compaired to the distance in the Earth's orbit!

"Do two telescopes 20 miles apart have the same view of the heavens? No! They are more than a fifth of a degree off -- that's HUGE."

Your 1/5 of a degree number seems meaningless. It may be 1/5 of a degree from the Earths core to two points 20 miles apart on its surface but so what? We are trying to calculate the position the Earth is along it

Each year German scientists leave a beacon along Earth's orbit. This crusty marker stays there until it is picked up next year, and the elapsed time is measured. This year, the time was different than expected. It's called the Hansul-Gretel algorythm.

It has nothing to do with "where the Earth is supposed to be". This is *not* about the earth orbiting the sun.

This is all about the earth spinning on its axis, 24 hours/revolution. As others mentioned, you can figure out quite precisely when the earth has made one revolution about its axis, by looking at a star.

The point is, slight variations in the earth's rotational speed on its axis mean that it doesn't take exactly 24 hrs 0 min 0.000 000 sec to turn once.

"At the National Institute for Science and Technology in Boulder, spokesman Fred McGehan said most scientists agree the Earth's orbit around the sun has been gradually slowing for millennia. But he said they don't have a good explanation for why it's suddenly on schedule."

"Orbit around the sun" doesn't sound like they are talking about rotation to me.

I don't think this should be that suprising. It is widely known that the moon's orbit is increasing. The effects of this is slowly causing the tides to be less severe. It is also slowing the earth's rotation. Eventually the moon will be in orbit around the equator, and there will be no more tide. I think there might be a good chance that the loss of the leap second could be related to this.

True. What he should have meant to say is that eventually the earth will be tidally locked with the moon (as the moon is already with the earth) and so the moon will no longer appear to rotate around us from the earth's PoV.

With the moon in geosynchronous orbit around us, we would naturally not experience any more tides from the moon, but we would still have the (lesser) tides caused by the sun.

Spare me please.
You all are the biggest bunch of need-something-to-whine-about babies I have seen in a good long time. So what if something was double posted? It takes half a second to scan the headline and realize that its a repeat. You take more time crawling all over each other to be the first to whine/complain/joke about the repeated story. For God sakes, ignore the post if your time is so precious!
"HELLO? What is the problem? I doubt I'll donate to Slashdot again!"
That is the saddest sentence I have ever had the misfortune of reading. Slashdot pours all kinds of blessings upon us geeks daily and you refuse to contribute BECAUSE A STORY WAS REPEATED? GOD FORBID! Burn them at the stake! They have wasted your precious half of a second!
Seriously folks, cry me a river.

If it only takes half a second, why don't they do it? On the most dupes day I've ever seen (3 - of stories still on the front page!), that would have taken, um, yeah, hmmmm. I'll let someone else do the math.

Why people complain about it is beyond me. Duplication of effort is a tradition in the open source world!
Plus, I've already wasted more than 30 earth-orbit-leap-seconds posting this.

> It takes half a second to scan the headline and realize that its a repeat

Did you notice this is the same kind of logic some spammers use when they try to convince others that spamming is harmless ? Something along the line of "It just takes a second to read, and if you don't like, just ignore it.".

Yeah but think of how many seconds of how many million geeks, wasted, i tell you WASTED! If any of the editors have the foresight to spend say 60 seconds checking, then the precious seconds of all the poor geeks in Asia and Africa will not belost, and to add ruthless insult to grieveous injury, even the cruel Earth has sought to deprived them of it since 1998. And I might add that if this continues, the terrorists would have already won. Spare a thought for the children.

The only thing that annoys me more than the whiners you speak of are the whiners who wine about people whining, which you are doing. Why don't you just shut the hell up and let people whine? Do you think you are imparting the community with some precious nugget of golden knowledge here? Take you own advice, and "For God sakes, ignore the post if your time is so precious!"

See, I could have just ignored you're post, but I chose to whine about it instead. It's quite a vicious circle you're a part of here.

AOL must have some way of directly converting energy into matter, specificly CDs ala Star Treks replicators. The proof being that if they arn't the entire earths resources would have been consumed 2 or 3 times over in their production via conventional means.

And all that energy to matter conversion has increased the mass of the Earth. Which has increased its gravatational field, and the effects of everything elses field on it. Thus the earth is moving faster.

To be sure, this is merely that there was no leap second yesterday. Slashdot has previously seen another story [slashdot.org] about the possibility that leap seconds might be discontinued permanently. Within the confines of that are links to everything that you could ever want to know about leap seconds, earth rotation, history of internecine wars between astronomers and physicists about time, etc.

If the Earth is assumed to be a homogeneous sphere and the rotational axis is assumed to be the straight line passing through the north and south geographic poles, the moment of inertia of the Earth is I = MR^2 where M is the total mass of the Earth and R is its radius. The kinetic energy of a rotating Earth is given by K = 1/2 I w^2, where w is the angular velocity.

The energy associated with an angular velocity which is increased by 1 second over a year is equivalent to an extra 1.6e22 Joules of energy or 40 times the annual energy consumption of mankind (DoE 1999). A detailed analysis and matlab script are available
here [michael-forman.com]

Yeah, this is a rereply. Whatever. It's a holiday. Nothing else to reply to.:)

If the Earth is assumed to be a homogeneous sphere and the rotational axis is assumed to be the straight line passing through the north and south geographic poles, the moment of inertia of the Earth is I = MR^2 where M is the total mass of the Earth and R is its radius. The kinetic energy of a rotating Earth is given by K = 1/2 I w^2, where w is the angular velocity.

With global warming, won't the radius increase, affecting this calculation?

What, when the radius of the earth increases by a few meters, mostly just because water expands? The rock isn't going to expand much in comparison.

The increase in the radius of the atmosphere is proportional to the increase in absolute temperature. At 0K, there's no atmosphere at all. I wouldn't be surprised if a few degrees C overall temperature increase would have a measurable effect on the radius of the planet.

For 28 years, scientists repeated the procedure [of adding a leap second]. But in 1999, they discovered the Earth was no longer lagging behind.

Um, not exactly true. Not every year over the last 28 years has had a leap second. For example, 1984, 1986 and 1987 didn't have a leap second. It's generally determined if a leap second is necessary about 6 months ahead of time by IERS [iers.org]. However, this is the first 5 year gap of no leap seconds.

It's interesting to note that the "leap second protocol" permits a "reverse" leap second - meaning a "short" minute. This is because the folks involved in defining the leap second realized that the rotation of the earth is not 100% predictable, and therefore they theorized that there could be a "fast spinning year" that would merit the loss of a second. This hasn't happened yet.

This whole rotation-of-earth-isn't-constant idea is pretty new (50 years). So just because we have a 5 year period of smaller rotaional speed deltas isn't totally unexpected.

Actually, not only is the article a dupe, but I just saw the old article linked on google news!

My new year's prediction: this article, having found a niche, will be continually resubmitted by clueless slashdot readers, reposted, and picked up by automated news services in a never-ending cycle of google-reader-slashdot that will ultimately threaten the very fabric of the internet itself!!

To make the world's official time agree with where the Earth actually is in space, scientists in 1972 started adding an extra "leap second" on the last day of the year.

"Where earth actually is in space"?

As HopeOS said when the previous article was posted:

"Leap seconds, as pointed out, are an entirely different beast, and are meant to shore up the discrepency between our actual rotation and the atomic clocks we use."

That's why. This has nothing to do with rotations around our sun, just around our own axis.

At the National Institute for Science and Technology in Boulder, spokesman Fred McGehan said most scientists agree the Earth's orbit around the sun has been gradually slowing for millennia.

Assuming this is true and this is the actual news here, the reporter (and the writer of the other article) shouldn't have started talking about leap seconds in the first place since these aren't added to compensate for that.

In addition to the fact that tides and the moon influence earth's rotation, so does weather.

Particularly, the monsoon season I believe has the largest effect, particularly because the generated winds impact the himalayan mountains.

The combination of a large (albeit distributed) force impacting a large object (himalayas) affects the angular velocity of the earth.

I learned this first because a friend was writing an ephermeris program and got in contact with the guy an NIST who tracks these things. I beleive they can make some predictions of change in rotational velocity based on the force of observed storms.

Also the Navy has built an array of (radio or laser, I forget) interferrometers located in (I believe) the rocky mountains which are used to measure the actual variances against star positions.

Well it's called bootstrapping for a reason;-) And yes this amounts to someone's job but its more useful (necessary) than your post suggests.

Anyhow no, this is not bogus, here roughly was my friend's conversation with the guy at NIST:

Engineer How do you calculate spatial position (exactly)?NIST Obviously first we know precession and nutation, these are easily predictable.Engineer So that's exact, the whole story?NIST No, there are some additional varriations.Engineer What are

Weather patterns are *observed* to be the largest (hard to predict), cause of variation in earth's position. in particular as I said, the effect of monsoons impacting the himalayas.

I've now read a few of your other posts and seen that you have a bit of mistrust of government spending, not a bad thing in and of itself. However in this case as in many others the assumption that something is unwarranted leads to erroneous conclusions.

I'm reminded of the US Senator who used to hand out the 'Golden Fleece'

How about instead of replacing slashdot, Taco just gives a hundred or so random subscribers the ability to mod a story as a dupe before it is officially posted for everyone else to read? It wouldn't be much harder to implement then mod points or metamoderation. If it wasn't a dupe then noone would have to do anything, but if it was a dupe then those "lucky" few could get someone's attention by clicking a "This is a dupe" link.
Regards,
Steve

There is an ability to report errors to 'daddypants', although it is just a remailer to the people who posted the article in the first place and was mainly intended for typos and 404s. Needs a 'this is a dupe' automated thing beside it.

Slashdot is behind the times. Its userbase has become a joke of groupthink and trolls, and the editors don't even read their links or posted stories anymore. It still has the momentum of a large fanbase, however, which just increases the stupidity because we have all these mistakes happening in front of a huge readership.

I have agreed to differ with CmdrTaco before, in retrospect he has firm beliefs and sticks to them, all power to him.

Now, there are some things that could be improved on SlashDot, and we all know that. But basically it's still the most popular and the userbase is too diverse for anyone to really do much. First thing I would change is the moderation choices. Other than Interesting or Insightful there is no other reasonable option. Scaling is a problem though, they already have to handle huge load on their

I am a PhD student in mathematical physics, but I'm afraid I don't have a complete answer for you.

Technically the Sun's mass is decreasing due to solar wind, neutrinos and light (light doesn't have rest mass, but it still carries away energy). However, the change caused by this is so minuscule you can neglect it for the purpose of Earth's orbit. The difference will not be measur

The cesium atomic clocks use a fundamental property of the cesium atom, the difference in energy between two states of the cesium atom. This is the same principle of physics that produces emission lines in a spectrogram when an element is heated. When an electron jumps from one state to another, it emits or absorbs a photon at a specific and fixed frequency. The atomic clock measures this frequency and uses it to keep an oscillator synchronized with the cesium atoms.

I seriously doubt my biological clock or bird migration would be affected by an extra millisecond or so... I can't think of how that would be possible. Sounds like the change would be slow enough for us to adapt without many problems. Also, aren't bird migrations more triggered by seasonal changes than exact times? What I'm saying is: if a season gets 0.05 second longer per year, a season would not end 0.05 seconds later than before, but whenever that season would end due to climate changes. These usually v